the efficiency of longwall systems in the case of using

Acta Montanistica Slovaca, Volume 25 (2020), 4; DOI: 10.46544/AMS.v25i4.06

The efficiency of longwall systems in the case of using different cutting technologies in the LW Bogdanka Artur DYCZKO1, Małgorzata MALEC2* and Dariusz PROSTAŃSKI2

Authors’ affiliations and addresses: 1 Mineral and Energy Economy Research Institute of the Polish Academy of Sciences, Wybickiego 7A, 31-261 Kraków, Poland e-mail: [email protected] 2 KOMAG Institute of Mining Technology, Pszczyńska 37, 44-101 Gliwice, Poland e-mail: [email protected] *Correspondence: Małgorzata Malec, KOMAG Institute of Mining Technology, Pszczyńska 37, 44-101 Gliwice, Poland tel. +48 32 237 45 14 e-mail: [email protected] How to cite this article: Dyczko, A., Malec, M. and Prostański, D. (2020). The efficiency of longwall systems in the case of using different cutting technologies in the LW Bogdanka. Acta Montanistica Slovaca, Volume 25 (4), 504-516 DOI: https://doi.org/10.46544/AMS.v25i4.06

Abstract The authors concentrated on some issues related to the sustainable development of the mining industry, i.e. on the management of fossil fuels deposits to achieve economic efficiency, environmental, as well as social acceptance. It should be borne in mind that Poland still belongs to the countries in which electric energy production and thermal energy production are based on hard coal and lignite. The research work results described in the article present efficiency assessment aspects in the case of different longwall technological systems in the LW Bogdanka. Advantages and disadvantages resulting from using shearer and plow systems are given. An impact of dilution in the run-of-mine on the coal quality is analyzed, and some recommendations emerging from this analysis are suggested. On the basis of the conducted in situ experiments, technical possibilities of reducing dirt are described. As an efficiency assessment is a multi-criterion process, so it requires continuous monitoring of production parameters. The article also contains an analysis of longwall systems in the aspect of dust control. An impact of mining, technical and technological parameters on generated dust amount, in particular in the case of a shearer-equipped longwall face, is discussed. In the conclusions, it is highlighted that an efficient assessment process in the case of longwall systems is complicated as an impact of different factors should be taken into consideration. It is suggested to use the data integration platform based on the Service Oriented Architecture (SOA). Due to the SOA, any mistakes in the scope of the functionality of individual systems can be detected very quickly. Such an approach is fundamental for the realization of the TPM (Total Productive Maintenance), leading to the creation of the so-called Mine of Smart Solutions. Keywords hard coal, production, efficiency, longwall system, shearer, plow, safety, dust control

© 2020 by the authors. Submitted for possible open access publication under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Artur DYCZKO et al. / Acta Montanistica Slovaca, Volume 25 (2020), Number 4, 504-516

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Introduction

At present, it is very popular to use the term 'sustainable development, which includes three main areas: environmental protection and rational management of natural resources, economic development and a just distribution of advantages resulting from it, a social development.

Looking at the above areas from the perspective of the mining sector, it can be stated that sustainable

development in mining consists of the management of fossil fuels deposits to achieve the activity which is efficient economically, environment friendly and approved by society. Poland belongs to a relatively small group of countries, where electric energy production and thermal energy production is based on solid fossil fuels such as hard coal and lignite. Due to coal reserves in Poland, this fuel is and will be a guarantee of energy security at present and in the near future. In the seventies of the last century, the Lublin Coal Basin's construction was started in Poland's eastern part. Due to some geological problems at the beginning of the mine construction, the first longwall face started its operation in 1986. A production capacity turn happened in 1988, and since then, the production rates have been increasing. The Mechanical Preparation Plant, enabling beneficiation of coal and an improvement of its quality, started its operation in 1992. In the Bogdanka Mine, the period of recent 40 years is full of problems caused by nature and technical obstacles, but it is also the period of mine modernization, reconstruction and expansion in very difficult mining-and-geological conditions. The restructuring process enabled the Bogdanka Mine to achieve the hard coal branch's leading position – top production capacity, top production concentration, and lowest costs.

It is important to consider a phenomenon of mineral dilution, which results from the mechanization of processes. This phenomenon is one of the key factors having an impact on the economic efficiency of coal winning processes. (Wright, 1983), (Ingler, 1984) and (Knissel, 1955) analyzed the phenomenon of deposits impoverishment. However, (Noppe, 2003) suggested the most popular classification of impoverishment into three main groups: primary impoverishment – coal–cutting with a roof layer and with a floor layer made by a shearer or a

roadheader, secondary impoverishment – cutting of uplifted floor or collecting rock from the roof-fall, third-rate impoverishment – including coal impurities during roof supports cleaning or mixing of dirt

generated during driving stone roadways with the coal run-of-mine from longwalls. Sources of dilutions in a longwall face are presented in Fig. 1.

Fig. 1. Sources of dilutions in a longwall face (Noppe, 2003)


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The first publications on dilutions appeared in 1971 (Popov, 1971). However, (Agoshkov, 1974) determined relationships among parameters and dilutions.

Other tests were conducted in the Stillwater Mine in Montana by (Annels, 1996). He concluded that impoverishment increases when the seam thickness decreases. Soviet scientists Kaplunov, Mielnikov, Agoshkov i Bajkov studied these issues as regards ore deposits (Agoshkov, 1974; Agoshkov, et al., 1973; Agoshkov at al., 1967; Bajkov, 1973; Bajkov, 1978; Bajkov & Kuchko, 1974; Kaplunov, 1938; Kaplunov, 1948; Mielnikov, 1973; Mielnikov, 1974). The results of their research work and tests were used for developing similar methods for the hard coal mining industry.

Management of hard coal seams in the Lublin Coal Basin revealed new mining and geological conditions, unrepeatable in other Polish coal basins. Additionally, a necessity of adapting to the requirements of coal purchasers made the coal producers from the Bogdanka Mine use more efficient cutting technologies and innovative management of seams characterized by changeable quality parameters.

Research objectives

Several methods, techniques and tools were used for an assessment of longwall systems in the Bogdanka Mine. They included as follows: an expert assessment of Polish and foreign literature, mathematical modelling, probabilistic modelling, analysis of agglomerations, assessment of economic efficiency.

The research methods presented above were used for confirming the fact that it is possible to achieve

economic results of rationalizing the coal winning process consisting of extracting less dirt, where it is geologically and technically justified. Technical and economic analysis should present and justify basic elements which are decisive in the management of mineral resources, in particular: a selection of deposit opening method and of deposit exploitation system, determining forecasted losses in

geological resources, a determination of basic mining-and-geological parameters, determining criteria of qualifying the reserves to

commercial reserves, a determination of costs of exploitation and beneficiation, a determination of economic indicators, which decide about exploitation efficiency of the deposit.

A simplified classification of technologies for coal seams extraction is shown in Fig. 2.

Fig. 2. Classification of technologies for coal seams extraction (Dyczko, 2018)

Technical and economic criteria of selecting a technology of a deposit extraction require a determination of

the following issues: cutting system of a deposit, roof control (roof fall, filling, retarded caving), geometry of workings and pillars, type of support, machines and equipment, quantitative and qualitative losses of useful minerals.

An implementation of a correct mining system and of correctly selected machinery reduces losses and

impoverishment significantly.


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For years, the basic system of exploitation used in the Polish mining industry has been a longwall system. It consists of extracting a part of a seam in a rectangular shape, limited by road-heading workings. Shield support monitoring system plays a vital role as regards roof control and operational safety (Jasiulek, 2019). This part of the longwall process is conducted with the use of a full or partial roof fall or filling in with stowing material. A schematic diagram of a longwall system is shown in Fig. 3

Fig. 3. 3D schematic diagram of a longwall system (Dyczko, 2018)

An operation of longwall faces of lengths from 250 to 300 m enables to obtain advantageous economic and

technical results. (Korski, 2019) investigated and analyzed the longwall complex efficient time and reasons for its decreasing. The advantages of longwall systems include a small number of development activities, low exploitation losses, big production concentration, easy roof control and a possibility of implementing fully mechanized systems. In recent years efficient exploitation of thin seams below 1.5 m became a real success. Aiming at rational and economic mining of coal deposits in thin seams, the Jastrzębska Coal Company and LW Bogdanka started exploitation with the use of plow systems.

Characteristics of coal seam No. 385/2 in the Bogdanka Mine

Mining-and-geological conditions, as well as technical-and-organizational factors, have a decisive impact

on the development of hard coal exploitation technology such as: depth of a deposit bedding, thickness of a deposit, deposit inclination, geological disturbances, occurrence of natural hazards.

As regards cutting technologies, the following parameters play a key role:

conditions of a seam bedding, in particular seam thickness, parameters of a longwall face, in particular its height, properties of coal expressed by a cuttability index and an angle of lateral crushing, required daily production rates.

In the case of coal seam No. 385/2, the mining-and-geological conditions were as follows:

deposit thickness: 1.2-1.6 m, seam drift bands thickness: 0.1-0.16 m, primary temperature of rocks: up to 32°C,

Goaf


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methane hazard: I category, workings with “c” degree, compressive strength of coal seam: 8-19 MPa, type of roof rocks/compressive strength,

moderately compact mudstone and aleuralit/4.5-38 MPa, type of floor rocks/compressive strength – mudstone

weakly compact mudstone and aleuralit/2.5-20 MPa, seam cuttability (acc. to Protodiakonow): 0.75÷1.20.

The maps of seam 385/2 are shown in Fig. 4.

Fig. 4. Map of 385/2 seam thickness and map of 385/2 seam dirt bands thickness (Dyczko, 2018)

Seam No. 385/2, at a depth of 950 m, is one of the richest and most regular hard coal seams in the Lublin

Coal Basin.

The efficiency of longwall systems at the Bogdanka Mine

The mining operations conducted at the Bogdanka Mine for over 30 years have been based on shearers. However, such systems' overall dimensions cause that they can be effectively used in the longwall faces of the height exceeding 1.6 m. In the case of mining the seams of 2.0÷2.5 m in thickness, the daily production rates from one longwall face reached up to 20 000 Mg/day of the coal run-of-mine, and for the longwall faces of the height 1.6-2.0 m – 15 000 Mg/day.

In Fig. 5 longwall systems, used in the Bogdanka Mine, are presented.

Fig. 5. Longwall systems operated in the Bogdanka Mine (Dyczko, 2018)

As it has already been mentioned before, for low shearer longwall faces, there is a necessity of increasing

the longwall height by cutting the roof and the floor layers, causing a generation of dilutions and thus a deterioration of the run-of-mine quality. In 2010, a plow system was implemented in the Bogdanka Mine to eliminate this disadvantage. Due to it, exploitation of seams of the thickness below 1.6 m became more efficient as it was possible to improve the quality of the run-of-mine by reducing the amount of cut roof and floor rock layers, so-called "clean extraction". A 1% reduction of dirt in the run-of-mine often resulted in a two-digit improvement of the production profitability, which has been presented on the example of American mines (Kryj et al., 2011).

An improvement of the run-of-mine quality is confirmed by two longwalls' production rates in seam No. 385. The first longwall 7/V/385, where a longwall system with a shearer was operated, obtained 68% of coal in


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the run-of-mine. The second longwall 1/VI/385 obtained the result of 75% of coal in the run-of-mine. Over the years 2008-2019, the Bogdanka Mine purchased four plow systems. The first one, purchased in 2009, enabled to achieve the daily production rate on the level of 10 000 Mg/day in seam No. 385/2, whose thickness was about 1.55 m. The average daily longwall advance reached 10.0 m, the average monthly advance – 247.4 m, the average time of plow operation – 5h 23 min, the average daily gross production rate – 8200 Mg and the total production rate over the period: April-October was 1382 thousand Mg.

The world record of the daily production rate from low seams, obtained at the LW Bogdanka, was 22400 Mg. However, this record was broken by the miners from the Pinnacle Mine (USA) in August 2019. Using an automatic plow system, Cat Gleit Hobel GH1600 in the longwall of the height 1.42 m and the length of 294 m; the daily production rate reached 29420 Mg (Cat® Longwall Plow System Helps Set Low-Sean Production Record). Not long afterwards, Bogdanka increased the level of daily production reached 33612 Mg in October 2019.

Another challenge, as regards the implementation of the plow technology, was the longwall 7/VII/385 of the 305 m length and of the panel length of 5 km in the seam of the thickness 1.25÷1.60 m. It was equipped with the plow system, which used to be operated in the longwall 1/VI/385. In 2014 two more plow systems were purchased by the Bogdanka Mine. At present, four plow systems seem to be sufficient to keep the production rates on the required level for several years to come. Both cutting technologies, i.e. shearer systems and plow systems, will be used in the case of four longwall faces to be mined. Six mechanization systems should be at the disposal of the Mine, for example, 3 plow systems and 3 shearer systems or 4 plow systems and 2 shearer systems. The most important factors having an impact on choosing a shearer or a plow technology are listed in Table 1.

Table 1. The most important factors having an impact on choosing a shearer or a plow technology (Dyczko, 2018)

Factor Plow Shearer

Geo

logi

cal

Seam thickness from 0.6 m to 2.3 m from 1.5 m to 6.0 m

Coal hardness comparable properties

Inclination longitudinal up to 45 deg up to 20 deg transverse gradient 45 deg, dip 20 deg gradient up to 20 deg, dip 20 deg

Passing of faults average good Seam corrugation a plow passes in an easier way due to a smaller length

Tech

nica

l

Roof conditions a smaller web depth facilitates a roof control frequent downfalls

Floor conditions comparable properties (bases of powered roof support units adapted to difficult conditions)

Granulation of run-of-mine a larger amount of thick coal sizing strongly disintegrated run-of-mine

Overall dimensions of workings requires wider workings most often, the return drive situated in the longwall face

Automation partly automated operation a significantly smaller degree of automation

Fully automated plow longwall systems enable to mine very thin seams. This operation is extremely

difficult in the case of shearers because shearers operators must follow an advancing machine. However, both in the plow and shearer longwalls, there are roof supports operators who operate the roof supports or supervise their operation in the case of an automated system. The longwall height of 1.5 m seems to be the limit for operators' work in the longwall face (Fig. 6).

Fig. 6. A difficult position of the operator in the shearer longwall face (Dyczko, 2018)


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In the publications of such researchers as (Biały, 2014; 2015; 2016; 2017; Karbownik, 1987; Lewińska & Dyczko, 2016; Lewińska, Matuła & Dyczko, 2017; Lisowski, 2001; Magda et al., 2002; Lorenz et al., 2002; Przybyła & Chmiela, 2002; Rajwa, 2007; Dyczko & Kopacz, 2008; Lubosik 2009; Sobczyk, 2009; Brzychczy, 2012; Wodarski & Bijańska, 2014; Grudziński, 2009, 2012; Turek, 2013; Kopacz, 2015 relationships among geological and mining parameters and their impact on the mine model, mining technology, costs of processes, quality of commercial products and economic efficiency of mines are presented.

Parameters of longwall faces equipped with shearers over the years 2010-2019 are shown in Table 2.

Table 2. Parameters of longwall faces equipped with shearers (Dyczko, 2018).

Longwall No

Period of face exploitation

Panel length Length

Average coal seam thickness

Average face height

% of ripping

Average daily advance

Average daily advance (net)

Average daily advance (gross)

Total coal production rate

Total run-of-mine production rate

Average coal output (net)

13/II (p.382) 12 2 564 310 2.25 2.53 12% 8.84 9 489.00 12 155.00 2 751 872.00 3 525 037.00 78.10%

3/II (p.382) 8.2 2 160 289 2.4 2.92 22% 10.3 10 975.20 15 938.00 2 304 846.00 3 347 046.00 68.90%

6/IV/385 7.2 1 363 297 1.78 2.17 22% 7.7 6 321.00 9 284.00 1 112 440.00 1 634 006.00 68.10%

9/IV/385 4.0 1 077 296 1.9 2.28 20% 10.6 8 972.40 12 743.00 915 163.00 1 299 758.00 70.40%

4/IV/385 16.0 3 096 294.5 1.8 2.16 20% 7.9 6 372.00 9 691.00 2 510 499.00 3 818 404.00 65.70%

7/IV/385 6 1 110 296 1.7 2.14 27% 7.2 6 522.24 9 467.88 887 024.70 1 287 631.90 68.89%

8/IV/385 6 1 070 296 1.65 2.09 29% 5.8 4 766.39 7 895.97 800 753.32 1 326 522.69 60.36%

2/I/385 11 1 640 313 1.4 2.01 39% 5.9 4 444.33 8 274.06 1 177 747.90 2 192 625.10 53.71%

3/I/385 10 1 601 313 1.43 1.97 35% 6.0 4 488.78 8 356.80 1 151 489.02 1 995 964.68 57.94%

8N 7 1 053 322 3.01 3.35 34% 6.0 7 626.15 12 870.99 1 441 342.15 2 432 617.77 59.25%

4/IV/389 9 2 240 296 2.07 2.52 18% 8.8 9 922.14 12 441.74 2 411 080.40 3 023 342.70 79.75%

3/IV/389 9 2 411 296 2.07 2.49 19% 9.0 9 822.92 12 317.32 2 551 587.47 3 401 372.27 75.10%

1/V/391 12 2450 310.5 2.42 2.79 18% 8.7 11 098.67 14 022.19 2 974 443.10 3 757 948.14 79.15%

2/V/391 11 2 450 310.5 2.37 2.63 17% 8.8 10 550.68 13 292.41 2 911 986.40 3 668 706.10 79.37%

3/V/391 13 2 472 310.5 2.36 2.5 23% 7.1 8 716.96 11 504.42 2 902 746.70 3 830 970.40 75.77%

4/V/391 9 1 827 310.5 2.37 2.68 20% 7.5 9 152.80 11 849.55 2 170 112.27 2 919 918.58 74.42%

Parameters of longwall faces equipped with plows over the years 2010-2019 are presented in Table 3.

Table 3. Parameters of longwall faces equipped with plows (Dyczko, 2018).

Longwall No

Period of face exploitation

Panel length Length

Average coal seam thickness

Average face height

% of ripping

Average daily advance

Average daily advance (net)

Average daily advance (gross)

Total coal production rate

Total run-of-mine production rate

Average coal output (net)

1/VI/385 III.2010-XI.2010 1 744 250 1.54 1.77 20% 7.5 6 016.31 7 988.08 1 040 820.83 1 381 937.80 75.32%

7/VII/385 X.2011-III.2013 5 022 300 1.43 1.68 25% 11.5 7 807.36 11 326.37 3 333 741.80 4 836 360.30 68.93%

1/VIII/385 VII.2013-II.2015 5 024 300 1.4 1.7 26% 10.3 6 901.72 10 075.42 3 264 511.60 4 765 674.20 68.50%

2/VIII/385 VII.2015-II.2017 5 021 300 1.36 1.72 30% 9.8 6 443.57 10 139.24 3 335 178.20 4 910 071.80 67.93%

2/VI/385 X.2012-VII.2013 2 310 250 1.54 1.93 28% 10.2 6 392.90 9 592.00 1 374 473.00 2 062 275.80 66.65%

6/VII/385 XI.2013-VII.2015 4 850 300 1.47 1.78 26% 10.2 6 937.23 10 096.19 3 315 996.30 4 825 979.20 68.71%

5/VII/385 XII.2015-IV.2017 4 685 300 1.58 1.9 26% 11.1 7 939.58 11 683.62 3 335 178.20 4 910 071.80 67.93%

3/VIII/385 IX.2017-XII.2018 3 460 300 1.39 1.73 30% 8.9 5 936.90 9 364.57 2 293 709.51 3 621 062.78 63.34%

3/VI/385 XI.2014-X.2015 2 295 250 1.48 1.97 34% 10.5 6 051.96 9 552.95 1 270 912.34 2 006 120.52 63.35%

4/VI/385 II.2017-X.2017 2 320 220 1.44 1.77 31% 10.6 5 033.71 8 011.47 1 082 248.70 1 722 465.10 62.83%


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5/VI/385 I.2018-VIII.2018 1 844 300 1.32 1.73 33% 8.5 6 629.01 10 369.71 1 186 592.98 1 856 178.41 63.93%

6/VI/385 XI.2018-VI.2019 1 600 300 1.35 1.68 30% 8.5 6 297.56 9 851.23 1 023 683.70 1 635 488.47 62.59%

1/I/385 V.2015-VII.2016 2 043 318 1.36 1.57 32% 6.4 4 454.80 6 975.00 1 505 716.47 2 357 556.57 63.87%

2/II/385 II.2017-XI.2017 1 640 318 1.35 1.72 30% 7.6 5 143.88 8 087.50 1 075 071.90 1 690 287.70 63.60%

3/II/385 VII.2018-IV.2019 1 640 318 1.17 1.55 34% 6.0 4 783.81 7 521.38 925 928.40 1 605 895.03 57.66%

According to the above tables' data, the average daily advance of plow longwalls is 9.2 m per day, while the

daily net advance of shearer longwalls is 7.9 m per day. However, the daily net production in the case of plow longwalls is about 2,000 tons lower than that of the longwall mining (6,185 tons per day vs 8,078 tons per day). This is due to the fact that the thickness of the excavated coal for plow longwalls was almost 30% lower in the period under consideration than it is in the case of shearer longwalls. At the same time, both the plow and shearer longwalls had a similar abundance, on average about 1.95 million tons per longwall.

Due to the specificity of available data, the analysis was conducted for the whole life cycle of a longwall face. The assessment process is presented in Fig. 7.

Fig. 7. Procedure and analytical assessment process of coal extraction economic efficiency (Dyczko, 2018)


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This analysis includes several key stages: preparation of data, a generation of big random samples, construction of an economic efficiency model.

The thematic scope includes geological data (ash content, calorific value, humidity, weight of run-of-mine), cost data, data analysis and construction of an economic efficiency model, an analysis of agglomerations, verification of results and finally, a generation of assessment results in the form of scenarios. This approach combines qualitative features of the run-of-mine with the features of the mining system and exploitation costs.

A model of economic efficiency assessment is also based on the data from empirical samples and the samples generated using the Monte Carlo method and grouped into 11 clusters implemented in the RapidMiner Studio 5 Software.

Analysis of longwall systems in the aspect of dust control

The necessity of reducing rock-dust concentration in the mine atmosphere is justified by the requirements

relating to workplace safety. Excessive dust content has a negative impact on the health conditions of the personnel working in the longwall face and the technical condition of machines, particularly their control systems (Myszkowski & Paschedag, 2013; Cernecky et al., 2015).

During an operation of a shearer, a lot of small-size coal dust concentrated on a relatively small area is generated as well. This kind of dust causes an explosion hazard. Particles of generated dust are ejected into the environment by a rotating cutting drum. Sizes and properties of the dust depend on the type of the coal being cut and on several parameters of the shearer, such as, for example: cutting drum diameter, number and arrangement of cutting picks, drum rotational speed, shearer haulage speed. An impact of selected parameters characterizing the cutting technology in a shearer-equipped longwall face is shown in Fig. 8.

Mine A: cutting without cowls against ventilation direction (1), cutting without cowls according to ventilation direction (2), Mine B: cutting with cowls against ventilation direction (3), cutting with cowls according to ventilation direction (4), Mine C: cutting with cowls according

to ventilation direction (5), cutting without cowls according to ventilation direction (6).

Fig. 8. Impact of mining, technical and technological parameters on dust amount in a shearer-equipped longwall face (Prostański, 2017) Longwall shearers are equipped with dedicated spraying systems to control dust. Spraying nozzles are

usually installed on the cutting drum directly behind cutting picks. As the result of multi-year tests (Prostański, 2017), a system of air-and-water spraying devices was implemented. The essential idea of the air-and-water spraying installation consists in delivering water and compressed air to spraying nozzles; these are produced by the cutting technologies (for example, Peterka et al., 2008). Due to atomization, its aerosol is ejected (Prostański, 2012). Streams of air-and-water aerosol, ejected from nozzles installed around the cutting drum and on the top edge of the ranging arm, generate a curtain separating the cutting zone (Prostański, 2013).

Despite a continuous operation of the spraying installation on the shearer, it is also indispensable to reduce dust in the case of other sources in a longwall face, for example, generated by the articulated face conveyor and advancing powered roof support units. A significant reduction of dust in a longwall face was achieved as the result of using the "KOMAG" system, equipped with assemblies of spraying nozzles installed on the canopies of powered roof support units. The system starts when the cutting operation begins. An operational control of the spraying installation was developed due to the use of empirical models presented in the project (Prostański,


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2015). An issue of modelling the zone protecting against a coal dust explosion propagation is presented in (Prostański, 2017).

In the case of cutting with a plow technology, bigger coal blocks are obtained in comparison to cutting with shearer technology. The plow technology generates smaller amounts of suspended dust, but an increase in the web depth causes a reduction of suspended dust amount and an increase in big coal blocks' contribution in the run-of-mine (Myszkowski&Padchedag, 2013). A more uniform distribution of generated dust along the face length is an advantageous phenomenon.

While cutting, the plow body always pushes a heap of the run-of-mine in front of it. Due to that, the plow picks cut the solid under the shield of the coal, which has already been mined, which suppresses an ejection of dust to the environment (Myszkwoski, 2004). In plow-equipped longwalls spraying systems are usually installed on the canopies of shield support units (for example, Prostański et al., 2017) or along the scraper conveyor.

The plow control system starts spraying nozzles only a few seconds before the plow passage and switches them off a few seconds after the plow body passes the nozzles. Due to tests relating to identifying the dust source in plow-equipped longwalls and assessing the applied dust control technology conducted in three plow-equipped longwalls, it was stated that the spraying system installed on the canopies of the shield units effectively eliminates dust generated during the cutting process. From the tests discussed in (McClland & Jankowski, 1998), it can be concluded that in comparison to the weight of the dust generated during a plow operation, the dust generated during the powered roof support advance has a bigger impact on the dust level in the longwall face. The biggest amount of dust (60%) is generated by a stationary crusher installed at the longwall inlet. Control of this dust is obtained due to an installation of a complex system of spraying nozzles presented in (McClland & Jankowski, 1998) on the crusher and discharge points. An efficient dust control of discharge points is possible due to an application of air-and-water spraying installations of BRYZA or VIRGA types (Prostański & Vargova, 2018).

Summary and final conclusions

The research work results presented in the article concern the efficiency assessment of longwall systems

using shearers and plows in the LW Bogdanka. Measurements were taken for several longwall faces using different extraction technologies in similar mining and geological conditions. An analysis of dilutions in the run-of-mine enabled to determine quality losses and their impact on underground mining systems' economic efficiency on the example of the Bogdanka Mine. On the basis of conducted in situ experiments, technical possibilities of reducing dirt are described. An optimation of the cutting machine operational trajectory reduces dilution as it enables to avoid cutting floor or roof layers containing small quantities of coal. The dirt has a negative impact on the quality of the run-of-mine, causing an increase of the ash content and thus a reduction of the feed calorific values directed to the preparation plant. It should be highlighted that an efficient assessment process is complicated, so it requires continuous monitoring of production processes. It is suggested to take advantage of the data integration platform using the SOA – Service Oriented Architecture. It is important that due to the SOA, any mistakes, as regards the functionality of individual systems, can be detected very quickly. In terms of underground mining conditions and transported loads, safe and optimal transport organization plays an important role in hard coal production processes. Researchers (Tokarczyk & Dudek 2020) have developed the Safe Trans Design system for computer aiding the configuration and assessment of auxiliary mine transportation means, which facilitates complex activities, minimizing the possibility of errors due to a human factor. Mechanization and automation of mining processes require a connection of management systems and keeping production archives with the maintenance of machines and equipment. Such an approach is fundamental for the realization of the TPM (Total Productive Maintenance) recommendations. This system is one of the LW Bogdanka strategic objectives oriented onto so-called Mine of Smart Solutions, taking advantage of innovative technical ideas to increase production efficiency at a simultaneous guarantee of miners' work safety and a minimalization of the negative environmental impact. An analysis of longwall systems in the aspect of dust control is important from the point of view of miners' health. Some recommendations concerning air-and-water spraying systems for longwall faces and the run-of-mine haulage routes contribute to effective dust control in underground workings.

The research results presented in the article contain practical recommendations concerning the efficient management of longwall systems. From the conducted analyses, it can be concluded that various barriers must be overcome. They are of technical, legislative, financial, organizational and institutional character (Malec, Stańczak & Ricketts 2020). The research processes conducted at the LW Bogdanka confirm the orientation of the authors on an industrial implementation of innovative solutions, being the result of collaboration between science and industry.


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References

Agoshkov M.J. (1974): Technical and Economic Assessment of Gaining Minerals from Rocks. Niedra Publishers, Moscow. (in Russian).

Agoshkov M.J., Panifilov E.J. (1973): Individual Classification of Losses in Mining Deposits of Hard Minerals. Gornyj Zhurnal (Mining Journal) No. 3. (in Russian).

Agoshkov M.J., Rysov P.A. (1967): Improvement of Methods of Calculating Losses and Impoverishment of Minerals in Mining Ore Deposits Using Roof Caving Systems. Gornyj Zhurnal (Mining Journal) No. 3. (in Russian).

Annels A.E. (1996): Assessment of Minerals Deposits – Practical Approach. 1st Edition. Chapman and Hall. UK. Bajkov B.N. (1973): Social-and-Economic Problems of Using Rocks. Niedra Publishers, Leningrad. (in

Russian). Bajkov B.N. (1978): Determination of Losses and Impoverishment in Opencast Mining of Colour Metallurgy.

Niedra Publishers, Moscow. (in Russian). Bajkov B.N., Kuchko W.S. (1974): Technical-and-Economic Assessment of Losses and Impoverishment in

Mining Operations, Niedra Publishers, Moscow. (in Russian). Biały W. (2014): Coal cutting force measurment systems - (CCFM). 14th SGEM GeoConference on Science and

Technologies In Geology, Exploration and Mining, SGEM2014 Conference Proceedings, June 17-26, 2014, Vol. III, BUŁGARIA ISBN 978-619-7105-09-4/ISSN 1314-2704. pp. 91-98.

Biały W. (2015): Innovative solutions applied in tools for determining coal mechanical proprerties. Management Systems in Production Engineering 4(20)/2015. ISSN 2299‐0461. pp. 202-209. DOI: 10.12914/MSPE-02-04-2015

Biały W. (2016): Determination of workloads in cutting head of longwall tumble heading machine. Management Systems in Production Engineering 1(21)/2016. ISSN 2299‐0461. pp. 45-54. DOI: 10.12914/MSPE-08-01-2016

Biały W. (2017): Application of quality management tools for evaluating the failure frequency of cutter-loader and plough mining systems. Archives of Minning Sciences, Volume 62, issue 2, 2017. pp. 243-252. ISSN 0860-7001. DOI 10.1515/amsc-2017-0018.

Brzychczy E. (2012): Modelling and Optimization Method of Exploitational Activities in a Multi-Plant Mining Enterprise. Cracow. AGH Publishers. Series: Dissertations and Monograph No. 245. (in Polish).

Cat® Longwall Plow System Helps Set Low-Sean Production Record. https://miningconnection.com/longwall/business_spotlights/article/cat_longwall_plow_system_helps_set_low-seam_production_record/ (Access date: 02.07.2020).

Cernecky J., Valentova K., Pivarciova E., & Bozek P. (2015): Ionization impact on the air cleaning efficiency in the interior. In Measurement Science Review Vol. 15, No. 4, pp. 156-166. ISSN 1335-8871

Dyczko A. (2018): Methodology for the assessment of the impact of out of seam dilution on the efficiency of hard coal production on the example of LW Bogdanka S.A. Doctoral thesis under scientific supervision of Prof. Roman Magda. AGH University of Science and Technology. Cracow. (in Polish).

Dyczko A., Kopacz M. (2008): Influence of Impoverishment on Forming Characteristics of Mining Investment Projects and Selected Production Figures Exemplified by a Copper Deposit. 21st World Mining Congress. Cracow.

Dyczko A., Kopacz M. (2008): Impact of Impoverishment on Shaping Values of Mining Investment Projects and Selected Production Parameters on the Example of Cooper Ore Deposit. Gospodarka Surowcami Mineralnymi (Management of Minerals Journal, Volume 24, pp. 251-264, IGSMiE PAN Publishers. Cracow. (in Polish).

Grudziński Z. (2009): Proposals of Price Structures for Steam Hard Coal and for Lignite. Energy Policy Journal (Polityka Energetyczna) 2012 (2/2), pp. 159-171. Cracow. (in Polish).

Grudziński Z. (2012): Methods of Competition Assessment of Domestic Hard Coal for a Production of Electric Energy. IGSMiE Pan, Series: Studies, Dissertations and Monographs, No. 180, Cracow. (in Polish).

Ingler D. (1984): Mining Methods, Rock Dilution and Ore Losses. Jasiulek, D., Bartoszek, S., Perůtka, K., Korshunov, A., Jagoda, J., & Płonka, M. (2019): Shield Support

Monitoring System-operation during the support setting. Acta Montanistica Slovaca. Kaplunov R.P (1938): Classification and Method of Determining Losses in Mining Ore Deposits. Gornyj

Zhurnal (Mining Journal), No. 10. (in Russian). Kaplunov R.P. (1948): Problems of Mining Industry. Uglietechizdat, Moscow. (in Russian). Karbownik A. (1987): Grounds of Designing Theory. Selected Issues for Mining Faculties. Silesian Technical

University. Gliwice. (in Polish). Knissel W., Jurgen H. and Fahlbusch M. (1955): Significance of Selective Mining Exploitation for Economical

and Environmentally Beneficial Underground Ore Mining. International Mineral Resources Engineering, Imperial College Press 5, 2 pp. 165-174.


515

Kopacz M. (2015): Assessment of Dirt Management in the Function of Changeable Level of Coal Net Index on Example of Hard Coal Mine. Gospodarka Surowcami Mineralnymi (Mineral Resources Management, Volume 31, Issue 3, pp. 121-144, Cracow. (in Polish).

Kopacz M. (2015): The Impact Assessment of Quality Parameters of Coal and Waste Rock on the Value of Mining Investment Projects – Hard Coal Deposits Mineral Resources Management, Volume 31, Issue 4, pp. 5-30.

Korski J. (2019): Longwall Complex Efficient Time and Reasons of Its Decreasing. Inżynieria Mineralna (Journal of the Polish Mineral Engineering Society, Issue 2, pp. 35-43.

Kryj, K., Szafarczyk, J., & Baic, I. (2011). Problem of Economic Impact of Spoil Excavation in Hard Coal Mines. ROCZNIK OCHRONA SRODOWISKA, 13, 1835-1846. (in Polish).

Lewińska, P., & Dyczko, A. (2016). Thermal digital terrain model of a coal spoil tip–a way of improving monitoring and early diagnostics of potential spontaneous combustion areas. Journal of Ecological Engineering, 17(4).

Lewińska, P., Matuła, R., & Dyczko, A. (2017, June). Integration of thermal digital 3D model and a MASW (Multichannel Analysis of Surface Wave) as a means of improving monitoring of spoil tip stability. In 2017 Baltic Geodetic Congress (BGC Geomatics) (pp. 232-236). IEEE.

Lisowski A. (2001): Grounds of Economic Efficiency of Underground Exploitation of Deposits. Katowice-Warsaw. PWN Publishers. (in Polish).

Lubosik Z. (2009): Geo-Engineering and Economic Criteria of Hard Coal Exploitation from Residual Seam Lots. GIG Scientific Projects. Mining and Environment. No 3. Katowice. (in Polish).

Lorenz U. (2002): Proposal of a New Steam Coal Selling Formula for Professional Power Sector. IGSMiE PAN Publishers. Series; Studies, Dissertations and Monographs. No. 112. Cracow. (in Polish).

Magda, R., Woźny, T., Kowalczyk, B., Głodzik, S., & Gryglik, D. (2002): Rationalization of a Model and Size of Hard Coal Mines in Economic Conditions at the Beginning of XXI Century. AGH Publishers. Cracow. (in Polish).

Malec, M., Stańczak, L., & Ricketts, B. (2020). Integrated Commercialization Model of Research and Development Project Results. Management Systems in Production Engineering, 28(4), 228-239.

McClland J.J., Jankowski R.A. (1998): Investigation of Dust Sources and Control Technology for Longwall Plow Operations. U.S. Department of Interior, Bureau of Mines. Information Circular 9173.

Mielnikov N. W. (1973): Rational Use of Mineral Deposits. Gornyj Zhurnal (Mining Journal) No. 1. Moscow. (in Russian).

Mielnikov N. W. (1974): Future Mining Operations. Gornyj Zhurnal (Mining Journal). No. 2. Moscow. (in Russian).

Myszkowski M. (2004): Erstellung eines Berechnungsmodels zur Auslegung und Optimierung von Hobelanlagen auf der Grundlage von Betriebsdaten experimentellen Untersuchungen Berlin. (in German).

Myszkowski, M., & Paschedag, U. (2013). Longwall Mining in Seams of Medium Thickness. Comparison of Plow and Shearer Performance under Comparable Conditions.

Noppe, M. (2003, November). The measurement and control of dilution in an underground coal operation. In Proceedings of the 5th mining geology conference. Bendigo.

Peterka J., Pokorny P., Vaclav S. (2008). CAM strategies and surface accuracy. Annals of DAAAM for 2008 & proceedings of the 19th international DAAAM symposium. Book Series: Annals of DAAAM and Proceedings, pp. 1061-1062.

Popov G. (1971): The Working of Mineral Deposits. 2nd Edition, MPr Publishers, Moscow. Prostański, D. (2012). Dust control with use of air-water spraying system. Archives of Mining Sciences, 57. Prostański, D. (2017). Empirical models of zones protecting against coal dust explosion. Archives of Mining

Sciences, 62. Prostański, D. (2015). Experimental study of coal dust deposition in mine workings with the use of empirical

models. Journal of Sustainable Mining, 14(2), 108-114. Prostański, D., & Vargová, M. (2018). Installation optimization of air-and-water sprinklers at belt conveyor

transfer points in the aspect of ventilation air dust reduction efficiency. Acta Montanistica Slovaca, 23(4). Prostański D. et al. (2017): Method and system for air-water spraying in the working area of mechanical coal

miner. Polish Patent 224886. Prostański, D. (2013). Use of air-and-water spraying systems for improving dust control in mines. Journal of

Sustainable Mining, 12(2), 29-34. Prostański D. (2017): Air-water spraying method for reducing the methane and coal dust explosion hazard as

well as for reducing the airborne dust concentration. KOMAG Scientific Projects. Monograph No. 51. Przybyła H. I., Chmiela A. (2007): Organization and Economics in Designing an Exploitation of Coal. Silesian

Technical University Publishers. Gliwice. (in Polish). Rajwa S. (2007): Impact of Selected Geo-Engineering Results on a Process of Production Preparation in Polish

Hard Coal Mines. GIG Scientific Projects. Mining and Environment No. 4. Katowice. (in Polish).


516

Reuther E.U. (1989): Lehrbuch der Bergbaukunde – 11 Auflage. (in German). Siegmund, M., Bałaga, D., Janáčová, D., & Kalita, M. (2020): Comparison of spraying nozzles operational

parameters of different design. Acta Montanistica Slovaca. Sobczyk E. J. (2009): Arduousness of Geological-and-Mining Conditions of Hard Coal and Its Impact of

Deposit Management. Series: Studies, Dissertations and Monographs, No. 150, Publishers: IGSMiE PAN, Cracow. (in Polish).

Tokarczyk, J., & Dudek, M. (2020). Methods for Computer Aiding the Configuration and Assessment of Auxiliary Mine Transportation Means. Management Systems in Production Engineering, 28(4), 268-275.

Turek M. (2013): Costs Management System in a Hard Coal Mine in the Cycle of Coal Face Operation. Publishers: Difin. Warsaw. (in Polish).

Wodarski K., Bijańska J. (2014): Assessment of Economic Efficiency and Exploitational Risk of Residual Deposits of Hard Coal. Scientific Books of the Silesian Technical University – Mining, Book No. 30. Gliwice. (in Polish).

Wright, E. A. (1983). Dilution and mining recovery-a review of the fundamentals.

the efficiency of longwall systems in the case of using

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